1. Field of the Invention
The present invention relates to grasping or gripping forceps for medical treatment which is used for gripping a living tissue, etc., of a subject, for example, in a laparoscopic surgery.
2. Description of the Related Art
Conventionally, a grasping or gripping forceps is known in, for example, Published Unexamined Japanese Patent Application 1-133907. In the forceps shown, a pair of gripping members are provided on the distal end of a sheath to be inserted into a body cavity of a subject through the cannula of a trocar/cannula device so as to allow these members to be opened and closed and an operation section is provided on a proximal end of the sheath so as to open and close the pair of gripping members. An operation shaft is inserted into the sheath so as to be movable back and forth. The distal end of the operation shaft is coupled to the gripping members through a link mechanism. The operation section comprises an operation handle fixed to the proximal end portion of the sheath and a movable operation handle swingable by a setscrew pin relative to the fixed operation handle.
The proximal end of the operation shaft is connected to the swinging operation end of the movable operation handle. When the movable operation handle is swung with the setscrew pin as a fulcrum, then the operation shaft is slidably moved back and forth to enable the pair of gripping members to be closed and opened through the link mechanism. By the remote operation at the operation section, the pair of gripping members are opened and closed to allow the living tissue in the body cavity, for example, an organ such as the gallbladder to be gripped thereby or released therefrom.
In this type of gripping forceps, care should be exercised not to tighten the distal gripping sections to an excessive extent by the swinging operation of the movable operation handle of the operation section. One countermeasure is to provide a stopper pin on that area of the fixed operation handle oppositely facing the movable operation handle so that, even when the movable operation handle is to be closed relative to the fixed operation handle to a more than necessary extent, the movable operation handle abuts against the projecting end of the stopper pin and is prevented from any further swinging movement.
In such conventional gripping forceps, the stopper pin, being projected from the area of the fixed operation handle, provides an obstacle from its operational point of view. Further, the stopper pin effectively acts as such when the distal gripping areas are closed, but serves no purpose when they are opened.
Further an amount of projection of the stopper pin is fixed and, therefore, the movable operation handle is stopped at all times to a given abutting position. In actual practice, however, various forms of living tissue have to be gripped as to-be-gripped objects and it is often of advantage to set the stopper position adjustable instead of setting it fixed.